The present disclosure relates to the field of sports or game balls, particularly inflatable game balls such as basketballs. More particularly, the disclosure relates to a multi-layered game ball having a foamed intermediate layer and a process for the manufacture thereof.
It is well known to produce a game ball having multiple layers of differing materials. Each layer of the multi-layer game ball is directed to providing a specific function or characteristic for a given performance requirement. For example, a game ball may be produced of two layers. The outer layer may provide for durability, feel and playability properties, etc., and the inner layer, such as a bladder, may provide for pressure retention. One or more intermediate layers may also be provided to improve compression, resilience, coefficient of restitution, etc. Multi-layer game balls therefore typically have superior performance characteristics over single layer balls.
U.S. Pat. No. 5,636,835 discloses a game ball that is made by placing panels of foamable (i.e. capable of later being foamed) rubber on the bladder. The foamable rubber panels are made from a type of rubber that is designed to foam upon application of heat. Narrow strips of seam material are then attached over the foamable rubber panels. The seam material has a raised portion and flanged portions. This arrangement is then cured (i.e., heated, etc.). During the curing process, the foamable rubber reacts to become a foamed sponge rubber layer. The foamed material also rises into the raised portion of the seam material. Exterior cover panels are then placed between seams to form a finished ball.
U.S. Pat. No. 5,681,233 discloses a game ball that is made by also placing a plurality of foamable panels on the bladder. However, strips of rubber are then placed in the gaps between adjacent panels. This arrangement is then cured (i.e., heated, etc.) so that the panels become foamed and the rubber strips fuse to the bladder and the sponge rubber panels, forming seams. Cover panels are also then placed between seams to form the finished ball.
U.S. Pat. Nos. 6,506,135 and 6,544,133 disclose sportsballs that are made by placing a plurality of cushion panels on the bladder, then placing strips of rubber in the gaps between adjacent cushion panels. The cushion panels comprise an inner rubber layer, a foamed layer, and an outer rubber layer. Upon heating, the rubber strips, inner rubber layer, and outer rubber layer melt together. Seams are formed at locations corresponding to the rubber strips.
It would desirable to produce a multi-layer sports ball having an improved foamed intermediate layer.